High-performance ball socket

ABSTRACT

A bearing shell for a ball and socket joint made of plastic as well as the ball and socket joint per se, wherein the bearing shell has first areas, which are subject to higher mechanical loads than the other areas of the bearing shell, wherein the material of the bearing shell forming the first areas is formed from a reinforced plastic, and the other areas are made of a less reinforced or unreinforced plastic.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional under 37 CFR 1.53(b) of pending priorapplication Ser. No. 10/895,122 filed Jul. 20, 2004 and claims thebenefit (35 U.S.C. § 120 and 365(c)) of International Application PCT/DE2003/002387 of Jul. 16, 2003, which designated inter alia the UnitedStates and which claims the priority of German Application DE 102 33489.7 of Jul. 24, 2002. The entire contents of each application ishereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention pertains to a bearing shell made of plastic for aball and socket joint, especially for motor vehicles as well as to theball and socket joint per se.

BACKGROUND OF THE INVENTION

A bearing shell of this class for ball and socket joints, especially formotor vehicles, is known from DE 29722507 U1. DE 29722507 U1 discloses abearing shell, which has slots for elastic deflection during themounting of a joint ball in the bearing shell, the slots extendessentially in the direction of the central axis of the bearing shell.The inner walls of the bearing shell have groove-like depressions, whichare used as grease depots for lubricating the ball and socket joint.Spacer nubs are provided on the outer walls of the bearing shell, whichpreset the position of the bearing shell in the ball and socket jointhousing. The spacer nubs generate a pretension, however slight, afterinsertion into the ball and socket joint housing due to the additionalmaterial, which presses the bearing shell against the joint ball due tobeing supported on the ball and socket joint housing. Pretensioning ofthe bearing shell in certain areas is definitely desirable, because thismakes it possible for the joint ball not to be lifted off from parts ofthe bearing shell even under load, so that the entire contact surface isavailable for the transmission of torques in the joint. However, thepretension brought about by the spacer nubs on the outer sides of thebearing shell acts on the entire bearing shell or the mounted joint balland consequently also in areas in which such a pretension counteractsthe actual task of the ball and socket joint, or leads to increased wearin certain areas, and thus shortens the service life of the ball andsocket joint. At the same time, the space needed for installation isincreased.

DE 19932789 A1 discloses a ball and socket joint in which the joint ballis enclosed in a manner adapted to the direction of the load to increasethe transmission of forces without requiring a larger space forinstallation. The areas of the joint ball that are loaded more heavilydue to the direction of the force, surround the bearing shell more thanthe less heavily loaded areas. However, the bearing shell must belengthened in this embodiment to mount the joint ball in the bearingshell, which is equivalent to a great mounting effort as well as a highload on the material, which may lead to rupture of the bearing shell.

The bearing shells according to DE 19932789 A1 as well as DE 29722507 U1are made homogeneously from a plastic by injection molding. This designleads in practice to the problem that if an inexpensive plastic is used,it is tribologically well suited in the unreinforced form but does nothave sufficient strength, or it has good strength properties due tofiber reinforcement. Good strength properties are, however, equivalentto a loss of the tribological properties in case of inexpensiveplastics. Pretensioning of the bearing shell to achieve bettertransmission of forces also cannot be achieved with these plasticsbecause of the lack of flexibility.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide a bearingshell and a ball and socket joint having a bearing shell that have anincreased service life due to their design.

This object is accomplished according to the present invention with abearing shell having first areas, which are subject to higher mechanicalloads than the other areas of the bearing shell, wherein the material ofthe bearing shell forming the first areas is made of a reinforcedplastic, and the other areas are made of a less reinforced orunreinforced plastic.

Depending on the field of use of the ball bearing, the ball bearingaccording to the present invention and consequently also the bearingshell according to the present invention can be loaded more stronglyeither radially or also axially. Under a radial or axial load, the areaof the bearing shell in which the joint ball is in contact because ofthe load (loading area) is compressed by the joint ball in the directionof the load.

If the bearing shell yields, the joint ball likewise moves in theloading direction by the amount by which the bearing shell yields. As aresult, the joint ball can lift off from the area located opposite theloaded area of the bearing shell (opposite means here in a directionopposite the direction of load). The areas of the bearing shell that areloaded less heavily are therefore made according to the presentinvention from an unreinforced or less reinforced plastic. Due to theresulting increase in the flexibility of the plastic, the bearing shellis pretensioned during the mounting, as a result of which the joint ballcannot lift off from the bearing shell any longer, so that all contactsurfaces of the bearing shell are in contact for transmitting forceseven under a heavy load. At the same time, the risk of free clearance ofthe joint ball in the bearing shell, which may lead to deflection andconsequently to failure of the joint, is reduced at the same time due tothe pretensioning of the bearing shell, which is thus achieved. Areasthat are exposed to higher loads have according to the present inventiona reinforced core, which counteracts the deformation and wear occurringunder load and thus reduces the amount by which the joint ball sinksunder heavy load due to the compression of the plastic. A bearing shellthus designed makes it advantageously possible to design the bearingshell with a large contact surface in one piece and at the same time tomake it from a highly fiber-reinforced material.

Another advantageous embodiment is obtained by means of a bearing shellthat is additionally provided with webs and slots. Due to theadvantageous arrangement of webs and slots on the bearing shell, thetolerance compensation achieved by the pretension can be additionallysupported by the pretension being able to be coordinated even moreaccurately with the type of the stress. In addition, webs and slots makepossible simple mounting without great stress of the reinforced, andconsequently less expandable areas, due to a defined elastic expansionof the bearing shell. The risk of rupture of the bearing shell due toexcessive expansion of the unelastic areas is thus advantageouslyreduced.

The bearing shell according to the present invention advantageously hasreinforced, and unreinforced or less reinforced areas. The reinforcedareas being manufactured, e.g., by means of a multicomponent system. Themulticomponent system is composed of reinforced plastics, and lessreinforced and/or unreinforced plastics. The reinforced area comprises acore component and a jacket component. Due to corresponding additives,e.g., fibers, mica, minerals, fillers or beads, the core component formsthe reinforcement, whose degree of reinforcement can be set variably byvarying the type and the amount of the reinforcing additives used. Thejacket component is formed by a tribologically suitable plastic. Itsurrounds the core component in the sections in which there may beincreased risk for wear due to friction effects because of correspondingreinforcing additives, e.g., between the core component and the jointball, and the susceptibility to wear of the ball and socket joint thusdecreases. The material costs can be lowered due to the use of theabove-described plastics and the bearing shell can thus be manufacturedat a lower cost.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are side views of a one-part bearing shell of a ball andsocket joint loaded mainly radially with axial and radial tolerancecompensation;

FIG. 3 is a cross section through the bearing shell according to FIGS. 1and 2;

FIGS. 4 and 5 are side views of a one-part bearing shell of a ball andsocket joint loaded mainly axially with axial and radial tolerancecompensation;

FIG. 6 is a side view of a one-part bearing shell of a ball and socketjoint loaded mainly axially in the form of a sleeve joint with axial andradial tolerance compensation;

FIG. 7 is the cross section of the bearing shell according to FIG. 6;

FIG. 8 is the side view of a multipart bearing shell with axial andradial tolerance compensation;

FIG. 9 is the cross section of a multipart bearing shell of a ball andsocket joint loaded mainly axially in the form of a support joint withaxial and radial tolerance compensation;

FIG. 10 is the cross section of a multipart bearing shell of a ball andsocket joint loaded mainly under tension in the form of an axial joint;

FIG. 11 is the cross section of a one-part bearing shell with definedsupport area; and

FIG. 12 is an enlarged view of a projection necessary for varying thesupport areas on the inner side of the bearing shell according to detailA.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, FIGS. 1 through 3 show a bearing shell 1 of aball and socket joint loaded mainly radially. The bearing shell has aone-part design and has a basic body 2, with which a bearing shell part3 comprising a joint ball is made integrally in one piece. To simplifythe mounting, the bearing shell 1 is provided with elastic webs 4 andslots 5, which enable the bearing shell 1 to expand elastically duringthe mounting operation. Weakening of the plastic, which is otherwisecommon, and which may lead to rupture of the bearing shell due to thestrain of the plastic during the mounting operation, is counteracted bythe elastic expansion already during the mounting operation.

The bearing shell according to FIG. 1 is intended mainly for radiallyloaded ball and socket joints. The elastic web 4 is designed such that,combined with a circular slot 5, the bearing shell can expandelastically without the application of any great force during themounting (see FIG. 3). The webs 4 later act as a tolerance compensationduring the mounting due to their elastic behavior, and they compensatethe tolerances of the housing and the ball. An increase in the axialtolerance compensation can be achieved by means of a rubber ring, whichis installed during the mounting of the bearing shell in the ball andsocket joint housing between the bearing shell and the ball and socketjoint housing. Differences in height that may possibly occur can thus becompensated during the mounting, as a result of which more uniformjoints can be manufactured.

FIG. 2 shows another side view of the bearing shell 1 of the ball andsocket joint loaded mainly radially. The bearing shell has a circularslot 5 along the bearing shell part 3. To increase the stability of thebearing shell before installation in a bearing shell housing, anotherweb 6 (indicated by broken line), which connects the bearing shell partswith one another, may be arranged on one side. Webs 7, likewiseindicated by broken line, may be optionally arranged in the basic body 2of the bearing shell 1 in order to achieve a radial tolerancecompensation by a corresponding pretension.

FIG. 3 shows a cross section of the bearing shell 1 according to FIG. 1.Corresponding to the type of load, the bearing shell 1 may be reinforcedon both sides, less reinforced or unreinforced on both sides as well asreinforced on one side and at the same time less reinforced orunreinforced on the other side. Both the basic body 2 and the bearingshell parts 3 have a two-component system, which comprises atribologically suitable jacket component 80 having a jacket surface 8,into which a core 9 reinforcing the plastic is inserted, on theright-hand side in the exemplary embodiment according to FIG. 3. Thecore 9 is reinforced with fibers 72, mica 74, minerals 76, fillers orbeads 78. The core 9 counteracts the deformation and wear occurring atan area 70 that is subject to higher mechanical loads. To manufacturethis system, a first plastic is first injected into the correspondinglyshaped cavity, the cavity being filled only partly. This material formsthe jacket surface of the two-component system. The cavity is filledcompletely in a second process step with a second plastic, which formsthe reinforced core component. Depending on the prevailing type of load,the basic body 2 of the bearing shell 1 may also be made unreinforced orslightly reinforced by a corresponding gating technique in order to thusachieve, for example, a higher pretension on the joint ball and toincrease the axial pretension as a result. The bearing shell 1 isreinforced less or is unreinforced on the left-hand side to increase thepretension. To increase the stability of the basic body, ribs 10 mayoptionally be made in one piece with the basic body. Furthermore, thebearing shell has openings 4 a on its inner side and/or outer side,which facilitate especially the elastic expansion of the bearing shellduring the mounting.

FIGS. 4 and 5 show exemplary embodiments of a bearing shell 11 of a balland socket joint loaded mainly axially. The bearing shell 11 may bereinforced on both sides, less reinforced or unreinforced on both sidesand reinforced on one side and at the same time less reinforced orunreinforced on the other side in this embodiment as well correspondingto the type of load. The corresponding webs 14 are arranged in the areasin which the lowest loads must be absorbed; this area is at the level ofthe equatorial plane in the exemplary embodiment (FIG. 4). The web 14 isused to facilitate the mounting as well as to generate a pretension ofthe bearing shell in this exemplary embodiment as well. To increase theradial tolerance compensation, an additional web 17 may be additionallyprovided at the basic body 12 (FIG. 5). The outer contour of the basicbody 12 may be either circular (FIG. 5, right) or oblique (FIG. 5, left)corresponding to the design specifications.

FIGS. 6 and 7 show a one-part bearing shell 21 of a ball and socketjoint loaded mainly axially in the form of a sleeve joint. Both elasticwebs (24, 27) and reinforcements of the plastic are arrangedcorresponding to the load. For example, the right-hand part of thebearing shell is made with an elastic web for axial tolerancecompensation in FIG. 6, whereas the left-hand part of the bearing shellis massive. Elastic webs 27 (indicated by broken lines in FIG. 6) mayoptionally also be arranged for radial pretensioning. Additionallongitudinal slots may be prepared in the bearing shell 21 for simplemounting. FIG. 7 shows a section through the bearing shell according toFIG. 6. The bearing shell has a two-component system 28, 29 (FIG. 7,left) on one side, and it is less reinforced or unreinforced on theother side (FIG. 7, right).

FIG. 8 shows a side view of a multipart bearing shell with axial andradial tolerance compensation. The axial tolerance compensation isachieved by integral material additions 34 in the form of projections,which are arranged such that they are compressed during the mounting ofthe bearing shell in the ball and socket joint housing and expand againin the areas in which the joint ball sinks corresponding to the load,and the clearance thus generated is again compensated. The integralmaterial additions 34 are arranged, for example, on the lower shell(FIG. 8, left), on the one hand, and on the upper shell (FIG. 8, right),on the other hand. The radial tolerance compensation as well as thepretensioning of the bearing shell after the mounting are made possibleby the corresponding arrangement of webs (cf. FIG. 2).

FIG. 9 shows a cross section of a multipart bearing shell 31 of a balland socket joint loaded mainly axially in the form of a support joint.Since compressive forces prevail in this embodiment, the plastic of thebearing shell sinks in the area of the contact surfaces of the jointball on the basic body 32. A great tolerance compensation, which iscorrespondingly necessary, is achieved by a greater pretension of thebearing shell 31 due to the use of bearing shell parts 33 with greaterwall thicknesses. The increase in the wall thickness of the bearingshell parts 33 arranged opposite the direction of the force causes anincrease in the pretension in the bearing shell 31, which is equivalentto stronger compression of the plastic during mounting. If the plasticis compressed in the area of the contact surfaces of the basic body 32during the loading of the support joint, the clearance generated in theprocess between the joint ball and the bearing shell parts 33 iscompensated by the relief of the elastic plastic of the bearing shellparts 33, which is pressed by the pretension. To counteract the sinking,the basic body 32 of the bearing shell 31 may have a reinforcing core39.

FIG. 10 shows a cross section through a multipart bearing shell 41 of aball and socket joint loaded mainly under tension in the form of anaxial joint. Corresponding to the load, mainly the area of the bearingshell parts 43 above the equatorial plane is provided with a reinforcingcore 49 here. Depending on the value of the load, the basic body 42 mayhave a greater wall thickness than the bearing shell parts in this caseas well; this is not shown in FIG. 10.

FIG. 11 shows a cross section of a bearing shell 51, which is reinforcedwith a core 59, is provided with elastic webs 54 and which makespossible, in addition to the above-mentioned features, to adapt theengaging support surface to the value of the load and thus to obtaindefined torques in the ball and socket joint by the arrangement ofprojections 55 (cf. FIG. 12) on the inner surfaces of the bearing shell.Both the basic body 52 and the bearing shell parts 53 have, for example,a reinforcing core 59. The contact surface of the joint ball with thebearing shell is formed alone by the projections 55 having the height Δsunder low loads. The joint ball displaces the plastic forming theprojections with increasing load, so that the entire inner surface 56 ofthe bearing shell 51 forms the contact surface of the joint ball and theentire surface of the ball socket is involved as a result in thetransmission of the forces. The forces are transmitted uniformly to theplastic, and the effective contact pressures are kept low, so that theplastic is loaded less and its creep is reduced.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. A bearing shell for a ball and socket joint, the bearing shellcomprising: a first and a second area made of plastic, said first areabeing made of a reinforced plastic more reinforced than a plastic ofsaid second area.
 2. A bearing shell in accordance with claim 1, whereinsaid bearing shell has a one-part design.
 3. A bearing shell inaccordance with claim 1, wherein one part of the bearing shell is abasic body and has a reinforcing core in areas in which higher loadsoccur and is reinforced less or is unreinforced in other areas.
 4. Abearing shell in accordance with claim 3, wherein another part of thebearing shell is a bearing shell part and is shaped to surround a jointball, said bearing shell part being fastened to said basic body.
 5. Abearing shell in accordance with claim 3, wherein said bearing shellpart is made in one piece with said basic body.
 6. A bearing shell inaccordance with claim 5, wherein said bearing shell part is connectedwith said basic body of the bearing shell via at least one web which isespecially elastic.
 7. A bearing shell in accordance with claim 5,wherein said bearing shell part has a reinforcing core in areas in whichhigh loads occur on the contact surfaces, and other areas of saidbearing shell part are less reinforced or unreinforced.
 8. A bearingshell in accordance with claim 5, wherein said bearing shell partdefines openings shaped to facilitate elastic expansion of the bearingshell during mounting.
 9. A bearing shell for a ball and socket joint,the bearing shell comprising: a first bearing shell section; a secondbearing shell section having a reinforcing core and a jacket componentcompletely jacketing the entire outer surface of said core, said corebeing composed of a first plastic material uniformly reinforced with oneof fibers, mica, minerals or beads, said jacket component being composedof a second plastic material either unreinforced or reinforced with oneof fibers, mica, minerals or beads, said first material being morereinforced than said second material, said first bearing shell sectionbeing connected to said second bearing shell section to form an integralbearing shell structure for receiving a joint ball of the ball andsocket joint.
 10. A bearing shell in accordance with claim 9, furthercomprising: an elastic web; a basic body element integrally connected tosaid bearing shell structure via said elastic web, said basic bodyhaving a basic body reinforcing core in areas in which higher loadsoccur, said basic body being reinforced less or unreinforced in otherareas.
 11. A bearing shell in accordance with claim 10, wherein saidbasic body has a basic body jacket component completely jacketing theouter surface of said basic body reinforcing core, said basic bodyreinforcing core being composed of a first basic body plastic materialuniformly reinforced with one of fibers, mica, minerals or beads, saidbasic body jacket component being composed of a second basic bodyplastic material either unreinforced or reinforced with one of fibers,mica, minerals or beads, said first basic body material being morereinforced than said second basic body material.
 12. A bearing shell inaccordance with claim 9, wherein said integral bearing shell structuredefines one of a slot and a web, said web including an elastic plastic,said web and said slot making possible one of axial and radial elasticexpansion of said integral bearing shell structure during mounting aswell as pretensioning and/or tolerance compensation of said integralbearing shell structure.
 13. A bearing shell in accordance with claim11, wherein said first basic body plastic material is the same as saidfirst plastic material of said second bearing shell section and saidsecond basic body plastic material is the same as said second plasticmaterial of said second bearing shell section.
 14. A bearing shell for aball and socket joint, the bearing shell comprising: a first bearingshell section; a second bearing shell section having a reinforcing coreand a jacket component completely jacketing the entire outer surface ofsaid core, said core being composed of a first plastic materialuniformly reinforced with one of fibers, mica, minerals or beads, saidjacket component being composed of a second plastic material eitherunreinforced or reinforced with one of fibers, mica, minerals or beads,said first material being more reinforced than said second material,said first bearing shell section being integrally connected to saidsecond bearing shell section to form an integral bearing shell part,said bearing shell part defining an opening for receiving a joint ballof the ball and socket joint; a connection element; a basic body elementintegrally connected to said bearing shell part via said connectionelement.
 15. A bearing shell in accordance with claim 14, wherein saidbasic body has a first section and a second section, said first sectionhaving a basic body reinforcing core and a basic body jacket componentcompletely covering the outer surface of said basic body reinforcingcore, said basic body reinforcing core being composed of a first basicbody plastic material uniformly reinforced with one of fibers, mica,minerals or beads, said basic body jacket component being composed of asecond basic body plastic material either unreinforced or reinforcedwith one of fibers, mica, minerals or beads, said first basic bodymaterial being more reinforced than said second basic body material. 16.A bearing shell in accordance with claim 14, wherein said bearing shellpart defines a slot, said connection element being composed of anelastic plastic, said connection element and said slot making possibleone of axial and radial elastic expansion of said integral bearing shellstructure during mounting as well as pretensioning and/or tolerancecompensation of said integral bearing shell structure.
 17. A bearingshell in accordance with claim 15, wherein said first basic body plasticmaterial is the same as said first plastic material of said secondbearing shell section and said second basic body plastic material is thesame as said second plastic material of said second bearing shellsection.